Weather strips comprising elongate base members which hold flat rubber strips to act as an air seal to provide a weather strip are well known in the art. For example, U.S. Pat. No. 2,612,664 to SIDDEN describes a weather strip for storm doors in which a strip of rubber is held within a metal base member which has a simple construction of a folded sheet of metal. Other weather strip constructions are known in which the rubber strip is specially formed to have a base portion which is wider, the base portion is then attached to a door frame using a bracket which secures the base portion of the rubber strip to a frame of the door to be sealed. An example of such a weather strip is disclosed in U.S. Pat. No. 4,312,153 to PARKINSON et al.
The prior art weather strips function well for one-way doors which are provided with a stop such that the rubber strip of the weather strip comes into contact with a portion of the door frame from only one direction. Conventional weather strips fail to be durable when used as weather strips for two-way doors in which the rubber strip flaps against the portion of the door frame in such a way that it flexes in both directions. It has been found that conventional weather strips have a tendency to tear as a result of the action of the rubber strip being flipped back and forth during two-way door movement while the rubber strip is held within its elongate base member. Although it is possible to use more sophisticated rubber sealing strip constructions, for example as disclosed in U.S. Pat. No. 4,419,844 to Kreisfeld or in the above-mentioned U.S. Pat. No. 4,312,153 where the wider base of the rubber strip is adapted to be fitted within a bracket such that flexion of the rubber strip does not cause a tearing of the rubber strip. such specially manufactured rubber strips are more costly to manufacture as a result of their use of materials and method of production.
In the case of dock levellers, it has been found that weather strips placed between the levellers and the surrounding truck loading bays deteriorate rapidly, usually as a result of a tearing or guillotine action on the weather strip as the leveller moves bidirectionally up or down with respect to the surrounding bay.
In the case of overhead doors, it has been found that weather strips placed across the top of truck docking bay doors are rapidly worn out by tearing since the weather strip is moved in two directions as the door moves up and down. The same deterioration, as a result of a tearing or guillotine action, accurs, especially when the flexible material of the weather strip becomes brittle in very cold weather.
In every case, maintaining a good seal in the weather strip is both important for heating or air conditioning energy conservation and for hygiene by keeping insects out. Effective weather strips in dock bays of warehouses represent significant energy savings.